ht_synapse – Synapse with depression after Hill & Tononi (2005)
===============================================================

Description
+++++++++++

This synapse implements the depression model described in [1]_, p 1678.

Synaptic dynamics are given by

.. math::

    P'(t) = ( 1 - P ) / \tau_P  \\
    P(T+) = (1 - \delta_P) P(T-)    \text{ for T : time of a spike } \\
    P(t=0) = 1

:math:`w(t) = w_{max} \cdot P(t)`   is the resulting synaptic weight

For implementation details see:
`HillTononi_model <../model_details/HillTononiModels.ipynb>`_

.. warning::

   This synaptic plasticity rule does not take
   :ref:`precise spike timing <sim_precise_spike_times>` into
   account. When calculating the weight update, the precise spike time part
   of the timestamp is ignored.

Parameters
++++++++++

The following parameters can be set in the status dictionary:

========  ======  =========================================================
 tau_P    ms      Synaptic vesicle pool recovery time constant
 delta_P  real    Fractional change in vesicle pool on incoming spikes
                  (unitless)
 P        real    Current size of the vesicle pool [unitless, 0 <= P <= 1]
========  ======  =========================================================

References
++++++++++

.. [1] Hill S, Tononi G (2005). Modeling sleep and wakefulness in the
       thalamocortical system. Journal of Neurophysiology. 93:1671-1698.
       DOI: https://doi.org/10.1152/jn.00915.2004

Transmits
+++++++++

SpikeEvent

See also
++++++++
:doc:`Synapse <index_synapse>`, :doc:`Hill-Tononi Plasticity <index_Hill-Tononi plasticity>`